My WiFi Shield 101 and a new Arduino Zero just arrived today and after the usual fight with Windows USB drivers I was able to start it through its paces. It came with Firmware version 19.3.0 already installed.

I have to assume that there have already been some 18 versions of the firmware and that future updates are likely, so I'm wondering if the procedure for updating firmware is available and also if the firmware source and build script are part of its Open Source.